FIELD: This invention is in the field of actions for pianos and specifically actions for upright pianos. More specifically, it is in the field of upright piano actions intended to provide, for upright pianos, playability similar to that of grand pianos.
PRIOR ART: It is well-known in the art that the "feel" or "playability" of grand pianos has been superior to that of upright pianos and, also, that grand pianos are considerably more expensive than uprights and require considerably more space. Therefore, in spite of the poorer playing capability of uprights, there has been and continues to be a market for them. Furthermore, there has been and continues to be a strong desire, if not need, for upright pianos with their cost and space saving advantage that have playing characteristics more like those of grand pianos.
U.S. Pat. No. 473,944 covers an upright piano action intended to rival grand piano actions in its playability. U.S. Pat. No. 896,763 covers an invention having a similar objective. U.S. Pat. Nos. 199,687, 682,616, 788,482, and 1,000,762 show other upright actions which were intended to emulate grand piano actions but were simpler and presumably less costly to manufacture and easier to maintain than those of U.S. Pat. Nos. 473,944 and 896,763. The action of U.S. Pat. No. 199,687 was manufactured for many years. (Note: there are additional specific references to prior art in the following Description of the Invention.)
Nevertheless, there is still no commercially available upright piano having playing characteristics approaching or equal to those of grand pianos. Yet it is logical to assume that the market for such a piano has increased significantly in recent years because of the increased value of space and the increased costs of pianos.
The failure of the prior art improvements to the traditional upright action to provide an upright piano action competitive with that of a grand piano can be attributed to at least three basic problems. The first is that in each case the added complications increase the costs enough to outweigh any commercial value of the improvements. The second is that the improved performance is achievable and achieved only when the action is finely adjusted and regulated, a condition which is difficult to attain and relatively difficult and expensive to maintain with the patented actions. Third, those adequately skilled in the art will recognize that the improvements disclosed in the prior art patents will not sufficiently affect the way the action feels and responds to a pianist to warrant the effort and expense of incorporating the improvements into the action.
In view of these problems, it is a primary objective of the subject invention to provide an upright piano action having playing characteristics rivaling those of a grand piano action. In particular, regarding playing characteristics, it is an objective to improve the repetition capability to the extent that a key can be reliably replayed when it is lifted only part way from the fully depressed position, as is possible with a grand action. Further, it is an objective that there be no discernable dynamic lost motion in the action. (Note: "dynamic lost motion," a term coined by the inventor for the functional characteristics which are the cause of the loose feel of the touch of the traditional upright action, will be defined in the Description of the Invention which follows.) Still further, it is an objective that the inertial characteristics of the actions do be commensurate with those of grand pianos. It is a further objective that these characteristics be attained without significant increases in the cost of the action due to increased complication or the like. Another objective is that the action be nearly as easy to adjust and maintain as the traditional upright action is and considerably easier than the traditional grand action. Another objective is that the action stay in adjustment at least as long as the traditional action.